Dual-Stage Compressor, Control Method Thereof and Air Conditioning Unit

ABSTRACT

The present disclosure relates to a dual-stage compressor, a control method thereof, and an air conditioning unit. The dual-stage compressor includes a low-pressure stage; a high-pressure stage connected in series with the low-pressure stage; and a volume ratio adjustment mechanism arranged at the high-pressure stage and configured to adjust the volume ratio of refrigerant compression at the high-pressure stage. When the final compression pressure of the compressor is lower or greater than the exhaust pressure, the volume ratio adjustment mechanism is operated to increase or reduce the volume ratio of refrigerant compression at the high-pressure stage so that the final compression pressure of the compressor is equal to the exhaust pressure, and overcompression and undercompression are improved to adapt to changes in external conditions, increase the energy efficiency of the compressor, and reduce the noise of the compressor.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is a U.S. National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/CN2020/098925, filed on Jun. 29, 2020, which is based upon and claims priority to Chinese (CN) Patent Application No. 201910860820.0, filed on Sep. 11, 2019, the entire contents of all of which are incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

The present disclosure relates to the technical field of a compressor, and in particular, to a dual-stage compressor, a control method thereof, and an air conditioning unit.

DESCRIPTION OF RELATED ART

Relevant single-stage compressors include a capacity adjustment mechanism. Under some conditions, when the unit operates at a relatively low load, the capacity adjustment mechanism is usually adopted to control a slider of the compressor to move and change the capacity of the compressor so as to meet the demand.

The capacity of the dual-stage compressor is usually changed by a way of variable frequency regulation, but this way cannot effectively adjust the internal volume ratio of the dual-stage compressor. When the final compression pressure of the compressor is not equal to the exhaust pressure, overcompression and undercompression occur so as to cause additional energy loss and also generate strong periodic exhaust noise.

SUMMARY OF THE DISCLOSURE

According to an aspect of some embodiments of the present disclosure, a dual-stage compressor includes a low-pressure stage, a high-pressure stage connected in series with the low-pressure stage, and a volume ratio adjustment mechanism arranged at the high-pressure stage and configured to adjust the volume ratio of refrigerant compression at the high-pressure stage.

In some embodiments, the compressor is a screw compressor, and the volume ratio adjustment mechanism includes a first slide valve adjustment mechanism configured to adjust an output position of an exhaust port at the high-pressure stage.

In some embodiments, the dual-stage compressor further includes a capacity adjustment mechanism arranged at the low-pressure stage and configured to adjust an output capacity of refrigerant compression at the low-pressure stage.

In some embodiments, the capacity adjustment mechanism includes a second slide valve adjustment mechanism configured to adjust the output capacity of a bypass port at the low-pressure stage.

In some embodiments, the capacity adjustment mechanism includes a plunger adjustment mechanism configured to implement capacity adjustment through a suction volume of a designated bypass.

In some embodiments, the capacity adjustment mechanism includes a rotation speed adjustment mechanism configured to control suction volume by changing the rotation speed of a motor so as to implement capacity adjustment.

In some embodiments, the dual-stage compressor further includes a first driving mechanism connected with the first slide valve adjustment mechanism and configured to drive the first slide valve adjustment mechanism to move.

In some embodiments, the dual-stage compressor further includes a second driving mechanism connected with the second slide valve adjustment mechanism and configured to drive the second slide valve adjustment mechanism to move.

The present disclosure further provides a control method of the compressor, and the control method includes: when a final compression pressure of the compressor is lower than an exhaust pressure of the compressor, operating the volume ratio adjustment mechanism to increase the volume ratio of refrigerant compression at the high-pressure stage; when the final compression pressure of the compressor is greater than the exhaust pressure, operating the volume ratio adjustment mechanism to reduce the volume ratio of refrigerant compression at the high-pressure stage.

The present disclosure further provides an air conditioning unit, including the dual-stage compressor.

In the foregoing embodiment, when the final compression pressure of the compressor is lower than the exhaust pressure, the volume ratio adjustment mechanism is operated to increase the volume ratio of refrigerant compression at the high-pressure stage so that the final compression pressure of the compressor is equal to the exhaust pressure; when the final compression pressure of the compressor is greater than the exhaust pressure, the volume ratio adjustment mechanism is operated to reduce the volume ratio of refrigerant compression at the high-pressure stage so that the final compression pressure of the compressor is equal to the exhaust pressure, and overcompression and undercompression are improved to adapt to changes in external conditions, increase the energy efficiency of the compressor, and reduce the noise of the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an overall structure of a dual-stage compressor according to some embodiments of the present disclosure;

FIG. 2 is a schematic structural diagram of a high-pressure stage of the dual-stage compressor as shown in FIG. 1; and

FIG. 3 is a schematic structural diagram of a low-pressure stage of the dual-stage compressor as shown in FIG. 1.

DETAILED DESCRIPTION

The following clearly and completely describes the technical solution in the embodiments with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are only some but not all of the embodiments of the present disclosure. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

It needs to be understood that, in the descriptions of the present disclosure, the orientation or position relationship indicated by terms such as “center”, “longitudinal”, “transverse”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “internal”, and “external” is usually based on the one as shown in the drawings, only for the purpose of facilitating and simplifying the descriptions of the present disclosure, rather than indicating or implying that referred devices or elements must have a specific orientation or be constructed and operated in a specific orientation, and thus these words cannot be understood as a limitation to the protection scope of the present disclosure.

Some embodiments of the present disclosure provide a dual-stage compressor, a control method thereof, and an air conditioning unit, so as to solve the technical problem in the related art that the dual-stage compressor has energy loss and noise caused due to inequality in the final compression pressure of the compressor and the exhaust pressure.

The final compression pressure of the compressor is the final compression pressure of the last stage (namely, a high-pressure stage) thereof.

FIG. 1 shows a dual-stage compressor provided by some embodiments of the present disclosure. The dual-stage compressor includes a low-pressure stage 10 and a high-pressure stage 20 connected in series with the low-pressure stage 10. The dual-stage compressor further includes a volume ratio adjustment mechanism 30 arranged at the high-pressure stage 20 and configured to adjust the volume ratio of refrigerant compression at the high-pressure stage 20.

By applying the technical solution of the present disclosure, when the final compression pressure of the compressor is lower than the exhaust pressure, the volume ratio adjustment mechanism 30 is operated to increase the volume ratio of refrigerant compression at the high-pressure stage 20 so that the final compression pressure of the compressor is equal to the exhaust pressure; when the final compression pressure of the compressor is greater than the exhaust pressure, the volume ratio adjustment mechanism 30 is operated to reduce the volume ratio of refrigerant compression at the high-pressure stage 20 so that the final compression pressure of the compressor is equal to the exhaust pressure, and overcompression and undercompression are improved to adapt to changes in external conditions, increase the energy efficiency of the compressor, and reduce the noise of the compressor.

In some embodiments, as shown in FIG. 2, the compressor is a screw compressor, and the volume ratio adjustment mechanism 30 includes a first slide valve adjustment mechanism configured to adjust the output position of an exhaust port 21 at the high-pressure stage. Refrigerants with different volume ratios are discharged from the high-pressure stage 20 by changing the output position of the exhaust port 21 at the high-pressure stage. For example, the closer the output position of the exhaust port 21 at the high-pressure stage is to the suction side of the screw compressor, the lower the volume ratio of the refrigerants is; the closer the output position of the exhaust port 21 at the high-pressure stage is to the exhaust side of the screw compressor, the higher the volume ratio of the refrigerants is. In use, the slide valve of the first slide valve adjustment mechanism moves towards the suction side of the screw compressor (the left side as shown in FIG. 2). At this time, the output position of the exhaust port 21 at the high-pressure stage moves toward the suction side of the screw compressor, so that the final compression pressure of the high-pressure stage 20 is reduced and equal to the exhaust pressure. By controlling the slide valve of the slide valve adjustment mechanism to a set position, the internal volume ratio of the high-pressure stage 20 is changed to match the final compression pressure of the compressor with the exhaust pressure, so as to reduce the noise of the compressor and improve the energy efficiency thereof.

As other optional implementation manner, the form of the volume ratio adjustment mechanism 30 is not limited to the slide valve adjustment mechanism.

In some embodiments, as shown in FIG. 1, the dual-stage compressor further includes a bearing 80 configured to support a rotor at the low-pressure stage 10 and a rotor at the high-pressure stage 20, and a motor 70 configured to drive the rotor at the low-pressure stage 10 and the rotor at the high-pressure stage 20.

As shown in FIGS. 1 and 3, in some embodiments, the dual-stage compressor further includes a capacity adjustment mechanism 40 arranged at the low-pressure stage 10 and configured to adjust the output capacity of refrigerant compression at the low-pressure stage 10. In some embodiments, the dual-stage compressor has the functions of capacity adjustment and internal volume ratio adjustment. For the dual-stage compressor, not only the capacity of the compressor can be adjusted according to external requirements to meet the demand of operations at different loads, but also the internal volume ratio of the compressor can be adjusted according to the change of external pressure to change the final compression pressure of the compressor and avoid the overcompression and undercompression of the compressor, so as to reduce the noise of the compressor and improve the energy efficiency of the compressor.

In some embodiments, the functions of capacity adjustment and internal volume ratio adjustment of the dual-stage compressor are used separately.

In some embodiments, as shown in FIG. 3, the capacity adjustment mechanism 40 includes a second slide valve adjustment mechanism configured to adjust the output capacity of a bypass port 11 at the low-pressure stage 10. When the front end of the slide valve of the second slide valve adjustment mechanism is in full contact with a stopper 12, the bypass port 11 of the low-pressure stage 10 is closed and the compressor is in a full load state. When requiring an operation at partial loads, the slide valve of the slide valve adjustment mechanism is adjusted to move towards the exhaust side (the right side as shown in FIG. 3) by a system, at this time, the bypass port 11 of the low-pressure stage 10 is connected with the suction side, that is, partial gas compressed is bypassed to the suction side and the actual suction volume is changed, so that the function of capacity adjustment can be implemented.

As other optional implementation manners, the capacity adjustment mechanism 40 may also be selected as a plunger adjustment mechanism configured to implement capacity adjustment through the suction volume of a designated bypass.

As another optional implementation manner, the capacity adjustment mechanism 40 may also be a rotation speed adjustment mechanism configured to control suction volume by changing the rotation speed of a motor so as to implement capacity adjustment. Optionally, in the technical solution of this embodiment, the capacity adjustment mechanism 40 includes a frequency converter, but the rotation speed adjustment mechanism is not limited to the frequency converter.

In some embodiments, the dual-stage compressor further includes a first driving mechanism 50 connected with the first slide valve adjustment mechanism and configured to drive the first slide valve adjustment mechanism to move.

In some embodiments, the dual-stage compressor further includes a second driving mechanism 60 connected with the second slide valve adjustment mechanism and configured to drive the second slide valve adjustment mechanism to move.

Optionally, both the first driving mechanism 50 and the second driving mechanism 60 include a movable cylinder, and the output end of the movable cylinder is connected with the first slide valve adjustment mechanism or the second slide valve adjustment mechanism so that the movable cylinder drives either the first slide valve adjustment mechanism or the second slide valve adjustment mechanism to move. Optionally, the movable cylinder is a hydraulic cylinder, or an air cylinder or an electric cylinder.

The above implementation manner is an example in which one form of capacity adjustment and internal volume ratio adjustment is selected. The stand-alone dual-stage screw compressor of the present disclosure can also be other forms capable of implementing capacity adjustment and internal volume ratio adjustment.

When the compressor is in operation and after the exhaust pressure changes, the final compression pressure of the compressor is not equal to the exhaust pressure. At this time, overcompression and undercompression occur, which brings the compressor about high noise and high power consumption.

The present disclosure also provides a control method of the dual-stage compressor, and the control method includes:

when the final compression pressure of the compressor is lower than the exhaust pressure, operating the volume ratio adjustment mechanism 30 to increase the volume ratio of refrigerant compression at the high-pressure stage of the compressor; or

when the final compression pressure of the compressor is greater than the exhaust pressure, operating the volume ratio adjustment mechanism 30 to reduce the volume ratio of refrigerant compression at the high-pressure stage of the compressor.

When the compressor is in operation and after the exhaust pressure changes, the final compression pressure of the compressor is not equal to the exhaust pressure. At this time, overcompression and undercompression occur, which brings the compressor about high noise and high power consumption. Therefore, at this time, the compressor is detected and compared for the final compression pressure and exhaust pressure to determine the pressure relationship, and an instruction for the movement direction of the output position of the high-pressure exhaust port is given. When the final compression pressure of the compressor is found not to be equal to the exhaust pressure, the exhaust pressure of the high-pressure stage 20 is adjusted to achieve the purpose of changing the final compression pressure of the compressor. When the final compression pressure of the compressor is lower than the exhaust pressure, the volume ratio adjustment mechanism 30 is operated to increase the volume ratio of refrigerant compression at the high-pressure stage 20; when the final compression pressure of the compressor is greater than the exhaust pressure, the volume ratio adjustment mechanism 30 is operated to reduce the volume ratio of refrigerant compression at the high-pressure stage 20.

Optionally, as shown in FIG. 2, with reference to the implementation manner of the slide valve adjustment mechanism, when the final compression pressure of the compressor is lower than the exhaust pressure, an instruction is issued to the first slide valve adjustment mechanism to move the slide valve towards the exhaust side (right side) and the position of the exhaust port moves backward, so that the final compression pressure of the high-pressure stage 20 is increased and equal to the exhaust pressure; when the final compression pressure of the compressor is greater than the exhaust pressure, an instruction is issued to the first slide valve adjustment mechanism to move the slide valve towards the suction side (left side). At this time, the position of the exhaust port moves forward, so that the final compression pressure of the high-pressure stage 20 is reduced and equal to the exhaust pressure. By controlling the slide valve of the slide valve adjustment mechanism to a set position, the internal volume ratio of the high-pressure stage is changed to match the final compression pressure of the compressor with the exhaust pressure, so as to reduce the noise of the compressor and improve the energy efficiency thereof.

By applying the technical solution of the present disclosure, when external pressure changes, the pressure relationship between the final compression pressure and exhaust pressure of the compressor is determined through detection, and an instruction is issued to the internal volume ratio adjustment structure; the position of the high-pressure exhaust port is adjusted, so that the final compression pressure is approximate to the exhaust pressure, and overcompression and undercompression are improved to adapt to changes in external conditions, increase the energy efficiency of the compressor, and reduce the noise of the compressor.

The present disclosure further provides an air conditioning unit, including the dual-stage compressor. The energy efficiency of the air conditioning unit can be improved by using the dual-stage compressor.

In the descriptions of the present disclosure, it should be understood that terms such as “first” and “second” are used to define parts, only for the ease of distinguishing the parts. Unless otherwise stated, the terms have no special meanings, and therefore cannot be understood as a limitation to the protection scope of the present disclosure.

Finally, it should be noted that the foregoing embodiments are merely intended for describing the technical solution of the present disclosure, but not for limiting the present disclosure. Although the present disclosure is described in detail with reference to the preferred embodiments, persons of ordinary skill in the art should understand that they may still make modifications to the specific implementation manners of the present disclosure or make equivalent replacements to some technical features thereof, without departing from the scope of the technical solution of the present disclosure. Such modifications and replacements should be covered within the technical solution claimed for protection by the present disclosure. 

1. A dual-stage compressor, comprising: a low-pressure stage; a high-pressure stage connected in series with the low-pressure stage; and a volume ratio adjustment mechanism arranged at the high-pressure stage and configured to adjust the volume ratio of refrigerant compression at the high-pressure stage.
 2. The dual-stage compressor according to claim 1, wherein the compressor is a screw compressor, and the volume ratio adjustment mechanism comprises a first slide valve adjustment mechanism configured to adjust an output position of an exhaust port at the high-pressure stage.
 3. The dual-stage compressor according to claim 1, further comprising a capacity adjustment mechanism arranged at the low-pressure stage and configured to adjust an output capacity of refrigerant compression at the low-pressure stage.
 4. The dual-stage compressor according to claim 3, wherein the capacity adjustment mechanism comprises a second slide valve adjustment mechanism configured to adjust the output capacity of a bypass port at the low-pressure stage.
 5. The dual-stage compressor according to claim 3, wherein the capacity adjustment mechanism comprises a plunger adjustment mechanism configured to implement capacity adjustment through a suction volume of a designated bypass.
 6. The dual-stage compressor according to claim 3, wherein the capacity adjustment mechanism comprises a rotation speed adjustment mechanism configured to control suction volume by changing the rotation speed of a motor so as to implement capacity adjustment.
 7. The dual-stage compressor according to claim 2, further comprising a first driving mechanism connected with the first slide valve adjustment mechanism and configured to drive the first slide valve adjustment mechanism to move.
 8. The dual-stage compressor according to claim 4, further comprising a second driving mechanism connected with the second slide valve adjustment mechanism and configured to drive the second slide valve adjustment mechanism to move.
 9. A control method of the dual-stage compressor according to claim 1, comprising: when a final compression pressure of the compressor is lower than an exhaust pressure of the compressor, operating the volume ratio adjustment mechanism to increase the volume ratio of refrigerant compression at the high-pressure stage; when the final compression pressure of the compressor is greater than the exhaust pressure, operating the volume ratio adjustment mechanism to reduce the volume ratio of refrigerant compression at the high-pressure stage.
 10. An air conditioning unit, comprising the dual-stage compressor according to claim
 1. 